[Mike Taylor 3601]

Cam walk on small/big block chevy happens on roller when timing cover flexes or cam button has to much clearance or if belt drive is'nt shimmed correct,cam moves forward and timing retards because cam gear comes forward does same thing as if you twisted dist.,and if it's severe enough lobes will start hitting sides of other lobes. I saw one idle @ 40 degrees and retard to 0 when revved,you could see timng cover bowed out.

If ford came forward it would advance timing

I have never seen any cam walk issues on ford,but cam walk acts like his description,but I also Tim's problem is more of interference like Buzzin half dozen said,I threw him out alot of things to check as always good to cover basics first.

In case anyone does'nt know and are wondering, flat tappets without thrust plate or method to keep cam from moving,the lobes are on taper so as cam turns the taper pulls cam rearward to keep time gear against block and located
Mike Taylor 3601